Film holding device for cameras



Feb. 10, 1959 A. M. GRASS I FILM HOLDING DEVICE FOR CAMERAS OriginalFiled April 1. 1952 2 sheetsesheet 1 INVEN TOR. ALBERT M. GRASSATTORNEYS Feb. 10, 1959 A. M. GRASS 2,872,842

FILM HOLDING DEVICE FOR CAMERAS Original Filed April 1, 1952 r 2Sheets-Sheet 2 Fig. 3

A I48 126 I50 Fig.4 1 W I i IN VEN TOR. ALBERT MGRASS United StatesPatent lice FILM HOLDING DEVICE FOR CAMERAS Albert M. rass, Quincy,Mass,

Original application April 1, 1952,-Serial No. 279,761,

now Patent No. 2,754,721, dated July-17, 1956. Diggiseggand thisapplication April 2, 1956, Serial No. 6 I

2,872,842 Patented Feb. 10, 1959 during exposure. Above the gates is adrive roller 44 which engages the back of the sensitized material, thatis, the shiny side of the film or the base of the paper and presses itagainst a rubber covered roll 46. In order to permit use of unperforatedfilm or paper, the roller 44 firmly engages the sensitized material andis therefore preferably formed with sharp longitudinal teeth in themanner of a spur gearas shown in Fig. 2, the teeth being indicated at47.. These engages the sensitized material with suflicient firmness toinsure precise transport, but they do not mar the surface.

Control roller 48 similar to the roller 44 is provided below the gatesand is adapted to engage the film between 'it and a rubber coveredroller 50, which is similar to the roller 46. While the roller 44is'used to drive the film, the roller 48is driven by the film and isitself used to control various operations to be presently described.

The movable'gate 42 and the rollers 46 and 50 are mounted on a laterallymovable carriage 52 which is operated by' a lever 54 through suitablelinkage 56 to move the gate and rubber rollers to the left and therebypermit cation, having provision for simple and ready transfer ofmagazines, and for simple threading of film into the camera.

With the foregoing and other objects in View, as will hereinafterappear, the present invention comprises the camera equipment hereinafterdescribed and particularly defined in the claims.

In the accompanying drawings, Fig. 1 is a side elevation of thepreferred form of camera; Fig. 2 is a detail of the feed roller; Fig. 3is a sectional elevation of the magazines, and Fig. 4 is a section online 44 of Fig. 3.

The apparatus shown in Fig. 1 comprises a base 10 within which isreceived the control equipment to be later described, and on which ismounted a drive motor 12. At the front of the base is mounted the cameraproper which comprises the exposure compartment 14 and the lens andshutter assembly 16. The shutter is preferably of the self cocking typeand is provided with internal contacts (not shown) similar to those usedfor flash synchronization and adapted to be closed when the shutterblades are wide open and to open immediately before the blades start toclose. A cable 18 leads from the shutter contacts to the controlcircuits in a manner to be later described. The shutter and lensassembly is mounted on a tube 20 which may be slid back and forthslightly with respect to the exposure chamber for purposes of focusing.

Two magazines 22 and 24 are provided. The supply of sensitized materialsuch as film or paper shown at 26 is contained within the supplymagazine 22. The supply is mounted on a core 28 which is supported on acentral shaft 30 with only sufficient friction to permit orderlyunrolling of the film without coiling. Alternatively, a spring brake 32may bear directly against the sensitized material itself, whereby thebraking action decreases as the size of the roll decreases thereby morecorrectly relating the braking action to the inertia of the roll.

The magazine 24 is a take-up magazine having a core 34 to which the filmis connected in any suitable manner. The core 34 is mounted on a shaft36 which is driven through a friction clutch at a speed suitable fortake-up in a manner to be described presently.

The length of film between the magazines runs through the magazine 22 ina manner described in said patent, and loops through the exposurechamber and thence to the take-up magazine 24.

Within the exposure chamber there is a fixed gate 40 and a movable gate42 between which the film is guided insertion of the film.

A 45-degree mirror 58 is mounted in back of the film gate 40 and isarranged to permit the rear of the film to be observed from the side ofthe apparatus for focusing and for other purposes as will be laterdescribed. The mirror is contained in a frame 60 and in back of theframe is a curved guide plate 62 over which the film passes. A secondguide plate 64 is spaced from the guide 62 and it runs 'under'the roller48 to terminate in an upwardly directed portion 66. The space betweenthe guides 62 and 64- forms a trough to permit threading of the filminto the camera. Entering the film into the trough is facilitated by aninclined guide plate 68 and a spool 70 at the upper part of the exposurechamber.

To thread the film the end of the film protruding from the supplymagazine 22 is threaded into the trough between the guides 62 and 64 andis pushed until its end appears above the portion 66 of the outer guard.At this time the carriage 52 will be at the left, thereby affordingsubstantial space between the toothed rollers 44 and 48 and theirrespective rubber rollers 46 and 50. A vertical plate may then beinserted against the part 66 of the guide plate, and upon furtheradvance of the film the end of the film will slide along the verticalplate to enter the take-up magazine 24. The end of the fihn is thenattached to the core 34 and the threading is completed, the verticalguide plate being then removed. The carriage 52 is then restored to itsposition whereby the film is closely maintained between the two gates 40and 42. A cover is provided for the exposure chamber and the cover has adark slide by which the rear of the film may be viewed in the mirror 58;focusing is done by adjusting the lens and shutter assembly until aclearly focused view is observed in the mirror. After the camera isthreaded, the focusing operation admits light only to a single frame andhence only the frame which is in position when the focusing operation isbeing carried on is wasted.

The motor may be driven at a number of speeds controlled by a switch 72on the base; preferably three speeds are provided. The motor isconnected through gears 74 with a change speed mechanism 76, which maybe of any suitable form. For the purposes of this description, it issufficient to state that the operation of the gear box is controlled bya sliding sleeve 78. The gear box, whatever its construction, ispreferably designed for a decade operation whereby the speed may becontrolled in jumps of 10. It has been found for most convenientoperation, the maximum film speed obtainable from the motor at fullspeed is one meter per second. The gear box preferably reduces the speedin the ratios and V1000 whereby speeds of meter, 1 cm. and 1 mm. persecond may be Obtained. The switch72preferably controls operation ofthe'motor at half and quarter speeds, so "that a still'finer selectionis obtainable. It will be seen, therefore, that the film speed isvariable in relatively small steps from .25 mmitol meter per second. f I

On the panel there is mounted a switch' tl by which the operator mayselectivelyiletermine continuous motion or framed motion'of the film.'A'manual switch 82 is used to initiate'the operation.

The electrical connections and the camera operations are fully describedin my above-mentioned patent.

The details of the magazines are'shown in Figs, 3 and 4; the supplymagazine 22 has'a'bo'ss 140,an d the takeup magazine 24 has a boss 142,both arranged to fit to gether as shown in Fig. Each boss carries alongscrew shown at 144 for the supply magazinq'and adapted to be fthr'ea'dedinto the top'of the frame' as"indicated'at'l'46. The magazines fit'tightly" on top of the frame andconnect with" slots148 and lj5fltherein.

The magazines arepi-ovided withli'ght traps, which 'for the supplymagazine 22 comprises a furcovered plate 152 suitably pivoted on themagazinepro'per and urged into closed position by a spring'154. Aipin 156 engagesthe upper end of the plate. The filmpasses over a roll 158"near the mouth of the magazine and also passes adjacent to a stationaryfur covered plate 160. Whenthe magazine is removed from the'frame thespring 154 urges the plate 152 against the stationary part160 and alsoagainst the roller 158, thereby preventing access 'of'light to theinterior of the magazine. Upon attachment 'ofthe magazines, however, thepin 156 is engaged'by a part'o'f the other magazin'e24 and presses 'onthe plate 152 in a'manner to open the light trap as 'shown' in'Fig; 3.Similarly,

magazine22'and opens the light trap of the magazine 24.

The magazines are provided with threaded covers to be received in thethreaded openings shown at 162 for the supply magazine, although thecovers are not shown in the drawings.

All parts of the drive should be such as to withstand the rapidaccelerations in'film transport. The gears of the gear mechanism 76 arepreferably of tough plastic such as nylon. The-take-up core 34' isnecessarily driven at a higher speed thanthe roll 44 and hence is driventhrough a suitable friction clutch mechanism'fwhich preferablycomprisesnylon members,.si nce"they have been found to give substantially thesame running friction as starting friction.

Having thus described the invention, I claim:

In a camera, a supply magazine, a take-up magazine, a frame on which themagazines may be mounted, each magazine having a pivoted light trap, aspring for each light trap normally urging it toward closed position,and pins carried by' the magazines, eachengaging its light trap at theendopp'osite'the spring and operated by engagement with theothermagazine to open its light trap when the magazines are positionedon theframe,

* References Cited inthe file ofthispatent UNITED STATES PATENTS1,087,996 Tessier Feb. 24, 1914 1,707,767 Ponting et al. Apr. 2, 19291,873,693 Gamble Sept. 20, 1932 FOREIGN PATENTS Switzerland Feb. 2, 1920

